How to use the fiber optic power meter and light source to measure loss?

The fiber optic power meter and light source are used together to measure loss in a fiber or fiber optic device. The source launches the light into one end of the fiber, while the power meter is connected to the other end to measure the received optical power. The source can be an optical laser or light emitting diode (LED) designed as part of a test set, or alternately the light wavelength communication equipment light source can be used.

Because optical fiber loss varies with light wavelength, power meter tests should be performed using the same wavelength as the one used by the light wavelength communication equipment. If light wavelength equipment operates at the 1310-nm wavelength, the power meter and light source should also be set to 1310-nm testing. If the light wavelength equipment operates at 1550 nm, the power meter and source should also beset to 1550 nm. Special consideration should be made when testing through a WDM network.